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