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