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