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