Grey sounds boring on the face of it but actually it's one of the most versatile colours in the spectrum. It's a neutral colour which not only helps create a calming and relaxing vibe, it also allows you to play with colour in other areas of your room without worrying about clashing, and changing up your bedroom design with the latest trend without having to buy another new bed.
You could also play with colour popping by placing a couple of brightly coloured cushions and or a blanket on the bed to give a burst of colour and contrast against the grey tones.