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