The Treklit sources say it's a guy in a hood.
Personally, I disagree with that. I say it represents an animal from Cardassia Prime. Why? Look VERY carefully at the tail of the Cardassian vole.
For whatever reason, this sort of tail appears in nature on Cardassia Prime. I therefore tend to suspect that the design of the Galor-class starship, and the design of the Cardassian sigil, is inspired by some sort of animal, which in my opinion is probably a form of undersea life not unlike the manta ray. The irony of that is that I see Cardassia Prime's oceans as being depleted and full of anoxic zones, so I'm not sure how common this ray is anymore. (But remember, the bald eagle was a symbol of the US even during the period when the bird was endangered.) It may have even gone extinct. If so, its rarity or extinction may well serve to galvanize the Cardassians to TAKE what their world has lost from others.
Not sure, but I think it fits the design a lot better than Treklit's "hooded warrior" theory.