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