There are folks here that convert every Yamaha style into something that will work on an S770 keyboard. Plus there are thousands of previous styles here for you to use on an S770 keyboard that came from all the previous Yamaha keyboards.
Genos and Tyros series have some Doo Woop voices (1950's stuff) that you will not have anything on your keyboard to replace those kind of voices. But if you take the time you can use one of the Chorus Voices that you have on the keyboard and record your own track into the style as a replacement.
If you are really into learning what the PSR, Genos and Tyros keyboards can do, there is no limit to what you yourself can create in the way of custom sounding styles.
Regards
Drake