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