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)(11,16)(12,25)(13,21)(14,19)(15,20)(17,23)(18,27)(22,36)(24,32)(26,35)(28,34)(29,31)(30,37)(33,38)(39,40)(1,3,4,8)(2,5,6,7)(9,11)(10,16)(12,22)(13,29)(14,23)(15,24)(17,19)(18,30)(20,32)(21,31)(25,36)(26,39)(27,37)(28,38)(33,34)(35,40)(9,11)(10,17)(12,22)(13,29)(14,23)(15,24)(16,21)(18,33)(19,32)(20,31)(25,30)(26,39)(27,37)(28,38)(34,40)(35,36) involution — undirected(9,12,14,27,15,28,13,26)(10,18,21,25,20,35,19,34)(11,22,23,37,24,38,29,39)(16,30,31,36,32,40,17,33)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.