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