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