IIRC, Clan Diamond Shark has mostly stuck with mixtures of dark blues and sea greens for their camos, with black trim on things like the joints. Additionally, they had shark teeth painted on mechs/battle armor/fighters that had at least 1 confirmed kill, similar to RL fighter nose art, just around their cockpits. If I were to aim for what I'd really want in the form of a pattern though, I'd like to see if it were possible to recreate the glimmering light effect that is created in the ocean. The name for the effect is escaping me at the moment, but this is a picture example.
Basically, trying to make it look it was underwater with light hitting it, with a shark tooth pattern around the cockpit. Probably not feasible, but hey, closest I can think of to a basic setup for what I'd want. Give or take the shark tooth pattern, probably, since they could add it as a decal if they wanted. And yes, I do know a shark teeth+mouth decal is in the game already, but I'm speaking of something like this:
but without the jaws. Basically just a more circular, shark-tooth version of the "Teeth" decal already ingame.
Anyways, even if you throw my ideas into the scrap heap, I'm just glad to know that the good folks at PGI are recognizing the factions we know and love, and hope I gave at least a little bit of insight into what might work.