Saruhiko makes every attempt to be distant and semi-professional with his co-workers however they don't make it easy. Despite being government employees who are able to maintain a professional demeanor in battle they still end up goofing off more than not. They're probably influenced by their captain who for all his stoic behavior spends much of his free time doing puzzles or tormenting his subordinates. Saruhiko isn't the type who normally wants to have fun or participate in team building exercises and yet he is continually dragged in by either his captain or his well meaning co-workers.
Saruhiko is a stern superior, he often critiques his subordinates reports and makes them redo it. That being said when they make minor mistakes he will often cover for them and redo it. When his co-workers stick around to help him (see Hidaka in Days of Blue) he will leave them energy drinks for their trouble. This is something of a habit he has, giving those he loves small gifts.
Despite his attitude Saruhiko works much better with Scepter 4 because he knows his job and all interactions with them are clear. It isn't like Homra where he was required to pretend he was part of a family when he didn't even know what a family should be. In Scepter 4 he knows where he stands which makes it far easier for him to get things done because he doesn't have to fear that he won't fit in.
Among his co-workers he's probably closest to Awashima Seri, the lieutenant of Scepter 4 and Munakata's second-in-command. She is perhaps more serious than Saruhiko and has been given the nickname of "tundra woman" by Homra. The two of them share the job of wrangling Munakata and they often end up allied in difficult situations. The two of them end up visiting Munakata's family because neither of them is willing to go alone.
Seri, like Munakata is extremely competent when it comes to her job and she knows how best to use the members of Scepter 4 to her advantage. She knows that she can discuss Munakata's condition with Saruhiko without concerning those below them. She will even support him when he goes off the rails and breaks protocol because she knows he can get things done. Saruhiko in turn keeps her grounded. He helps her kill spiders, the one thing she fears. He also stops her from going after Mikoto, thus saving her life and probably Scepter 4 headquarters as well.
Among other members of Scepter 4 there are mixed opinions. Enomoto and Gotou seem to accept him but are overall wary of invoking his wrath. Benzai and Kamo remain indifferent from what's been shown thus far, but that is likely because they are more mature than younger members like Andy Domyouji. Doumyouji and Fuse seem to dislike him. It is clear that Andy and Saruhiko fail to get along because their personalities clash. Andy being carefree while Saruhiko takes his job seriously. Finally Akiyama and Hidaka seem to like Saruhiko. In Hidaka's case it is only after some quality time doing reports that he begins to understand and accept Saruhiko. Even so he still won't put up with his crap. Akiyama is focused on his work and Saruhiko has learned to respect him, he often speaks more formally around Akiyama and although there haven't been any stories explaining how he earned that respect they have almost a tentative friendship.