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