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