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