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