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