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