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