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)(25,26,29,32)(27,34,37,40)(28,33,30,38)(31,39,35,36)(3,7)(5,8)(10,14)(15,20)(16,21)(22,24)(25,26)(27,35)(28,38)(29,32)(30,33)(31,37)(34,39)(36,40) involution — undirected(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,18)(13,17)(14,20)(16,22)(19,23)(21,24)(25,27,29,37)(26,31,32,35)(28,36,30,39)(33,40,38,34)(2,6)(3,7)(11,17)(15,20)(18,23)(22,24)(26,32)(31,35)(33,38)(34,40) involution — undirected(9,12,13,19)(10,16,14,21)(11,18,17,23)(15,22,20,24)(25,28,29,30)(26,33,32,38)(27,36,37,39)(31,40,35,34)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.