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