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