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