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