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