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