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)(11,21)(12,26)(13,29)(14,19)(15,30)(16,24)(17,18)(20,28)(22,39)(23,27)(25,34)(31,38)(32,40)(33,35)(36,37) involution — undirected(2,6)(7,8)(9,11,14,24)(10,16,19,21)(12,27,29,40)(13,23,26,32)(15,31,28,25)(17,35,36,39)(18,22,37,33)(20,38,30,34)(1,3,5,4)(2,7,6,8)(9,12,28,37,14,29,15,18)(10,17,30,13,19,36,20,26)(11,22,31,40,24,33,25,27)(16,32,38,39,21,23,34,35)(1,4,5,3)(2,8,6,7)(9,13,28,36,14,26,15,17)(10,18,30,12,19,37,20,29)(11,23,31,35,24,32,25,39)(16,33,38,27,21,22,34,40)(2,6)(7,8)(10,19)(12,29)(16,21)(18,37)(20,30)(22,33)(27,40)(34,38) 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.