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