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