The game shows all rogues (Thieves, Bards) as hooded.

Presumably characters aren’t wearing onesies with hoods! So the hood to me implies a hooded cloak. That’s just left to the imagination, of course. But that’s what I went with.
And there are many enchanted cloaks in the game. I’ll often give Imoen the Nymph Cloak to boost her Charisma to get the best prices from merchants, or Algernon’s Cloak to Charm enemies. But I also like the Cloak of Non-detection for her, especially when playing with the SCS mod installed. I keep her class as pure Thief and like to have her backstab with the Dagger of Venom. The Cloak of Non-detection allows her to remain in stealth mode should (SCS’s AI-enhanced) enemy mages cast Detect Invisibility, Oracle, True Sight or True Seeing. And the “Whispers of Silence” cloak, aka Cloak of Non-detection, actually is shown with a hood on in it in it’s item description in the inventory screen.

So I like to think of the cloak she’s wearing as the Whispers of Silence.
I chose purple for the cloak’s color. Imoen’s portrait has her in a purple top, and there’s purple hue in the background. I chose a wine color for her base clothing in order to feature a more realistic feeling contrasting color, i.e., not have her entirely in purple. (See the pic of the sprite shown above for reference.)

So I found this cloak on eBay. It has some rather poorly applied weathering effects, i.e., its dirtied up just at the bottom, plus some unconvincing mud splatters that are very light colored:

This stock cloak has very clean scissor lines as well. Not very realistic looking!
Therefore I got to work on it first with a steel wire brush which made the texture more coarse and worn. As such I added tears and tatters, and I frayed the edges. Then I applied black and brown washes along the edges and applied weathering powders.





The iPhone camera in the low-light charcoal colored box that I designed to photograph figures makes the cloak look almost pink-ish here. But it’s purple. Here’s the cloak in more natural light:
