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