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