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