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