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