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