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