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