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