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