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