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