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