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