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