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