Sunan Abi Dawud Book 35, Hadith 52
The Prophet (ﷺ) used to wear tanned leather sandals and dye his beard yellow with wars and saffron, and Ibn 'Umar used to do that too.
He did not dye his hair, but Abu Bakr and 'Umar dyed their hair.
When a man who had dyed himself with henna passed by the Prophet (ﷺ), he said: How fine this is! When another man who had dyed himself with henna and katam passed by, he said: This is better than that. Then another man who had dyed himself with yellow dye, passed by, he said: This is better than all that.