I doubt I'll go down well with this post, and probably rightly so, but to me there's a particular look I can associate with most if not all of the aspergic people I've known.
I think to complement the lack of subtle facial expressions people like me make, we don't have very "subtle" faces. It's quite hard to describe, but I find me and the others I've known have rather "blockish" faces, lumpy noses and even skin that appears thicker, as if we were drawn with a wider paintbrush. I feel like not only can I be as refined as other people, I can't look as refined as them either.
That's just my anecdotal observation though. Pretty much what phrenology was based on I'd imagine.