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