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