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