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