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