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