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