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