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