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