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