How can I get from Foshan to Guilin (bus,train) when leaving after 2200?

There is no direct train between these two places. And according to your departure time, there is no long-distance bus that can take you to Guilin.
You are suggested to stay at FS in the night. And go to Guilin in the next early morning.
Six long-distance buses for this route are scheduled from 10:30 to 17:30 at Dali Bus Station. The ticket fare is CNY 160 per adult. This bus station is not in the downtown.
Or you can take the bus at FS Bus Station. There is only one long-distance bus to Guilin with the schedule of 09:50am. The ticket fare is CNY 186.