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