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