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