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