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