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