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