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