The transmission solenoid on a 2000 Chevy Cavalier isn't located in one single place. The Cavalier's automatic transmission uses several solenoids, and they're all *inside* the transmission itself. You won't find them externally accessible under the hood or easily visible anywhere else.
To access the solenoids, you'd need to remove the transmission from the vehicle and disassemble it. This is a job for a professional transmission mechanic. There's no easy external access to them.
