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