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