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