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