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