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