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