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