There are two reasons why your sprinklers would continue running:
It's possible your valves have been opened manually. You'll need to locate your valve box(es) and turn the solenoid(s) clockwise until snug. The solenoid is located on the top of the valve and looks like a cylinder with two wires protruding out of it.
It's also possible that there is debris in the valve, which is causing the valves diaphragm to remain open.
To try and fix this:
disassemble the valve
rinse all the parts with clean water
re-assemble the valve.
If you cannot locate your valves it is recommended you contact the contractor who installed the system.