The air pressure when the pressure tank is empty should be 2 pounds less than the pressure that the switch turns on at. For example, a 40 to 60 PSI pressure switch would have an air charge of 38 PSI in the pressure tank when it is empty. It is important to have your tank empty of water when making adjustments as a full tank will not read correctly for it's pre-charge air pressure. Your switch is cutting off at 60 and there is usually about a 20 PSI difference between kick on and kick off pressures.
Set the air pressure to 38 PSI.