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