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