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