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