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