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