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