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