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