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