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