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