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