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