Yes - it is very important to clean the camera after each dive. Otherwise, the magnets will eventually rust.
The best way to clean the camera is to use lukewarm fresh water and submerge the camera for a few minutes.
When submerged, it is a good idea to turn the selector ring and pull the activation switch few times.
If the camera was used in very salty water - or is used very often - it is a good idea to remove the selector ring, clean the ring underneath and apply o-ring grease on both sides of the magnet.
This will help repel the water.
You can watch this video about the further maintenance of the camera.