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