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