Switch off the electrical breaker on the main power panel that provides current to the dryer.
Unplug the dryer, and pull the appliance away from the wall so you'll have enough room to work.
Unfasten the faceplate retaining screws, as well as the screws in the outlet, using a screwdriver. Pull the outlet out of the wall by hand, or use pliers to pull it out.
Disconnect the wires with a screwdriver, or cut the wires away from the outlet, using wire cutters.
Cover the ends of the wires with wire nuts. Leave the breaker switched off until you replace the receptacle.