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