(1) The words are written in a different-coloured ink.
To me, "a different-coloured ink" is nonsense because:
one colour corresponds to one ink;
different coloures can correspond only to different inks;
different coloures cannot correspond to one ink.
Why does "a different-coloured ink" make sense?
(2) The words are written in different-coloured inks.
What is the difference between (1) and (2)?