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