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