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