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