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