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