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