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