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