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