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