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