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