One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(11,19)(12,13)(15,22)(16,17)(20,21)(23,24)(33,39)(37,40) involution — undirected(2,5)(6,8)(9,10,14,18)(11,15,20,23)(12,16,13,17)(19,22,21,24)(25,26,29,32)(27,30,34,38)(28,35,36,31)(33,40,39,37)(1,3,4,7)(2,6,5,8)(9,11)(10,15)(12,21)(13,19)(14,20)(16,24)(17,22)(18,23)(25,27)(26,30)(28,33)(29,34)(31,37)(32,38)(35,40)(36,39)(9,11)(10,15)(12,19)(13,21)(14,20)(16,22)(17,24)(18,23)(25,28)(26,31)(27,33)(29,36)(30,37)(32,35)(34,39)(38,40) involution — undirectedA 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.