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