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