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