Here's a map of the OTL Ummayads at their greatest extent. Gives you a pretty good idea of where the Arabs expanded into.
And four hypothetical alternatives that I can think of:
1) Down the Nile.
2) Down the African coast.
3) Onto the Eastern European plains.
4) Into India.
Maybe a variation of the hypothetical East African Coast (2) and Indian (4) maps, albeit not as far south along the East African coast and expanding more into roughly the Balochistan region as well as the southern parts of Central Asia then into India proper?
