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