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