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