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