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