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