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