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