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