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