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