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