One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,3)(4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67)(5,37)(7,39)(9,41)(11,43)(13,45)(15,47)(17,49)(19,51)(21,53)(23,55)(25,57)(27,59)(29,61)(31,63)(33,65)(35,67) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.