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