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