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