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