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