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