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