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