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