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