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