As many people go grey their skin cools down along with their hair colour, but not everyone has cool grey hair and cool skin. Some people's skin remains warm even though their hair has cooled and greyed, and if they choose not to colour it, find that it can look a little odd if they are still wearing their warmer colours of the past. You still need to keep your colours on the warm end of the warm/cool divide, as otherwise you will look washed out and pale. But you may need to add in some elements of coolness to tone with your hair.
Add some grey into your outfit, but ensure they are warm greys rather than cool ones. You could also wear more silver jewellery, or mixes of gold and silver.
