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