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