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