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