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