The white LED is very bright, so this is the simplest way (and without voiding your warranty) to change the colour of the LED, and make it slightly less bright.
Use a small piece of coloured electrical tape to cover the LED. Just cut a strip about 7mm or so long, and wrap it over the LED and under the PCB. Simple, cheap, quick, very effective and totally reversible!
Other less convenient options could be to use a permanent marker to colour it in, glass paint, perhaps even nail polish. However be careful because some of these can be conductive and effect the circuit. They're also much harder to reverse.