Came to life again, we hear, with natural colour (6)
I believe the answer is:
undyed
'with natural colour' is the definition.
(not dyed)
'came to life again we hear' is the wordplay.
'came to life again' becomes 'undied' ('un-die' could mean to come back to life).
'we hear' indicates a 'sounds like' (homophone) clue.
'undied' sounds like 'UNDYED'.
(Other definitions for undyed that I've seen before include "Without artificial colouring" , "Not coloured" .)