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