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