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