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