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