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