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