How do I stop the high-pitched noise while brewing coffee?

When I plug the coffee maker in ( the switch doesn't work, the device is always on), there is a high-pitched noise that is present while the device is on. I make my coffee and then unplug it, so my coworkers around me don't get too mad at me.

Any idea why this high-pitched noise is happening? The only thing I can think of, is that it's related to the switch not working.