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