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