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