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