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