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