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