Make sure the keg remains at the proper temperature and proper pressure. It is not an issue if the keg coupler remains tapped into the keg, or is untapped. But be sure to clean the faucet, beer hose, and keg coupler with beer line cleaning chemicals before dispensing again. And keep in mind that all draft beer has a shelf life, and should be consumed before the flavor diminishes.
If you are going to be shutting off the refrigerator and putting it in storage, be sure to thoroughly clean the unit beforehand. This includes cleaning the faucet, beer line, and keg coupler with beer line cleaning chemicals. Cleaning the drip tray, and wiping the entire unit clean and drying the interior thoroughly. And lastly place an open box of baking soda inside the refrigerator to absorb any moisture that may cause mildew.
Then when it is taken out of storage, the faucet, beer line, and keg coupler should be cleaned once again before dispensing beer.