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)(11,15,13,16)(19,20)(23,24)(25,26)(27,31)(28,36)(29,30)(32,37)(33,34)(35,40)(38,39)(1,3,5,8)(2,4,6,7)(9,11,14,13)(10,15,12,16)(18,22)(23,24)(26,30)(27,33)(32,36)(35,39)(2,6)(3,8)(9,12,14,10)(11,15,13,16)(17,18,21,22)(19,23,20,24)(25,26)(27,34)(28,36)(29,30)(31,33)(32,37)(35,38)(39,40)(1,4)(2,3)(5,7)(6,8)(17,19,21,20)(18,23,22,24)(25,27,29,33)(26,31,30,34)(28,35,37,39)(32,38,36,40)(1,3)(2,4)(5,8)(6,7)(9,13,14,11)(10,15,12,16)(17,20,21,19)(18,24,22,23)(25,28,29,37)(26,32,30,36)(27,35,33,39)(31,38,34,40)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.