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