Well, would Renegade and Chaos actually be different?
Because Renegade doesn't necessarily mean Chaos-corrupted. It means independent, cut off from their Chapter if it still exists and the Imperium. It's jury-rigged equipment and scavenged weapons. Rugged, battle-tested, proud, desperate. It's defaced or at least faded iconography. Vox displays and text that fizzle or scatter momentarily. Names for the heads of the different chapter roles could change to something more straight forward, less gothic. (Chief Psyker for example.) Requisition would change to Resources. Loyalty would stay loyalty, except now it's to the Chapter Master instead of the Imperium.
Chaos...there's several ways you can approach it. There's the almost comical level of spikes, which would look sort of silly on UI buttons and panels. But some spikes, maybe with skulls on them, are always good. There's the liquid black metal look, the oil-slick precision of corrupted tech. There's the runic look with glowing runes and energy coursing through them. There's the melding of flesh and metal look, the blatant weirdness of warp flesh look. Daemonic skin and bone growths and nodules. Good 'ol pustules. The singular twitching eye, the twisted screaming faces woven into surfaces. And then there's just the artfully ancient and malevolent, age-crusted lines that still have an edge of elegance, pride and wrath. Green screens could be changed to red or like a faint purple. Names could change to more Chaos appropriate things. Your Chief Librarian would be your Sorcerer Lord or something. Your Chaplain may or may not change. They don't really have the same role as Space Marine chaplains. Only the Word Bearers to my knowledge have a Chaplain like role in their hierarchy. I suppose something like Master of the Cult, or something? Forgemaster could probably stay this same although I'm sure some Chaos-y alternative could be found (Forge Lord?) Loyalty would become Favor.