Xbox One continues make noise

When you turn it off the system goes into a sleep mode that allows it to maintain game progress as well as application data. This in turn will keep the system active for a little while after shutdown.

If you don’t want it to persist you can change this in the system settings to do a full shutdown instead.

Another way to ensure a full shutdown manually, you can hold the power button on the xbox itself until the light goes out and you’ll be able to hear everything come to a halt, but this is overtime harmful to the system OS and memory.

Best of luck!