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