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