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