One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6)(7,15)(8,11)(9,13)(10,19)(12,17)(14,18)(16,20)(21,22)(23,27)(24,29)(25,28)(26,30)(31,34)(32,36)(33,35) involution — undirected(1,2)(3,4)(5,7,9,8)(6,11,13,15)(10,16,18,17)(12,14,20,19)(21,23,26,33)(22,27,30,35)(24,32,25,31)(28,34,29,36)(1,3,4,2)(5,8,9,7)(6,12,13,20)(10,16,18,17)(11,14,15,19)(22,28)(23,31)(24,25)(29,30)(32,33)(34,36)(7,8)(11,15)(12,20)(16,17)(21,24,26,25)(22,29,30,28)(23,31,33,32)(27,34,35,36)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.