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)(25,26,29,31)(27,35,37,33)(28,34,30,39)(32,38,40,36)(1,2)(3,7)(4,8)(5,6)(9,11,14,21)(10,15,17,19)(12,20,13,22)(16,23,18,24)(26,31)(32,40)(33,35)(34,39)(2,6)(7,8)(9,12,14,13)(10,16,17,18)(11,20,21,22)(15,23,19,24)(25,27)(26,32)(28,36)(29,37)(30,38)(31,40)(33,34)(35,39)(1,3,5,4)(2,7,6,8)(10,17)(15,19)(16,18)(23,24)(25,27)(26,33)(28,38)(29,37)(30,36)(31,35)(32,34)(39,40)(1,4,5,3)(2,7,6,8)(9,13,14,12)(10,18,17,16)(11,20,21,22)(15,23,19,24)(25,28,29,30)(26,34,31,39)(27,36,37,38)(32,33,40,35)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.