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