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