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