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