You'll probably have minimal luck finding someone with premade genre lists for the whole list of games that MAME supports because the games that MAME supports changes on a pretty consistent basis.
You'll probably have better luck if you asked, "How can I create my own genre lists of MAME games easily?"
To which I'd personaly reply, "Download the latest catver.ini file, then download ListGen, ListGen.NET, or MAMEWAH Config (since you're using MAMEWAH)."
--Steve