Well the visual style may be different based on the colors but I would assume most of them (except the Ka Po Tun) to have a European look. I will assume Skyrim's are all black dragons and look European and the red dragon in Redguard has a European dragon style as well. The dragon skeleton in Battlespire also looks like a pure European style dragon. If that helps.
The only dragon we have a screenshot of so far was a wyvern.
Also, it wasn't black. It was like brownish. Well, it could go either way. The wings certainly weren't black though.