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