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