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