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