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