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