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