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)(11,16)(12,13)(14,15)(19,23)(21,24)(26,30)(27,33)(32,37)(34,39)(2,3)(4,8)(10,15)(11,13)(17,18,20,22)(19,21,23,24)(27,33)(31,36)(34,39)(38,40)(2,3)(6,7)(9,11,14,13)(10,16,15,12)(25,26)(27,31)(28,32)(29,30)(33,36)(34,38)(35,37)(39,40)(1,3,5,2)(4,7,8,6)(9,12,14,16)(10,11,15,13)(17,19)(18,21)(20,23)(22,24)(25,27)(26,31)(28,34)(29,33)(30,36)(32,38)(35,39)(37,40)(1,4,5,8)(2,6,3,7)(9,13,14,11)(10,16,15,12)(25,28,29,35)(26,32,30,37)(27,34,33,39)(31,38,36,40)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.