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