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