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