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