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