One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,11)(12,26)(13,27)(14,28)(15,29)(30,46)(31,47)(32,48)(33,49)(34,50)(35,51)(52,61)(53,62)(54,63)(55,64)(65,67) involution — undirected(1,2,3)(4,5,6,12,7,13,16,30,8,14,17,31,20,33,36,52,9,15,18,32,21,34,37,53,23,35,39,54,42,55,56,65,10,11,19,26,22,27,38,46,24,28,40,47,43,49,57,61,25,29,41,48,44,50,58,62,45,51,59,63,60,64,66,67)A 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.