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