There has been a facinating thread about this previously (here ).

Interestingly, I have a different colour palette to play from than Tom.

Chords: Am = beige, Bm=Dark blue C=red, D=brown, Em=purple, G=pale yellow

The keys roughly correspond. I was at a session recently where we normally play a mix and match of Irish, English and other snippets of music, but because of the make up of sessioneers we played mainly English tunes all night and the key of G dominated. I was cheesed off by the end of the evening because it was all pale yellow.