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)(11,16)(12,23)(13,26)(14,29)(15,20)(17,22)(18,28)(19,30)(21,35)(24,31)(25,32)(27,39)(33,38)(34,40)(36,37) involution — undirected(2,5)(6,8)(9,11,15,22)(10,16,20,17)(12,14,25,30)(13,21,27,36)(18,33,34,31)(19,23,29,32)(24,28,38,40)(26,35,39,37)(1,3,4,7)(2,6,5,8)(9,12,14,22,15,25,30,11)(10,17,19,23,20,16,29,32)(13,24,28,36,27,38,40,21)(18,33,26,37,34,31,39,35)(9,13,15,27)(10,18)(11,21,22,36)(12,24,25,38)(14,28,30,40)(16,31)(17,33)(19,26)(20,34)(23,37)(29,39)(32,35)(2,5)(6,8)(13,27)(18,34)(21,36)(24,38)(26,39)(28,40)(31,33)(35,37) 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.