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)(27,28)(29,37)(30,31)(32,34)(33,38)(35,39)(36,40) involution — undirected(1,2,4,5)(3,6,7,8)(9,11,15,13)(10,16,17,19)(12,21,20,23)(14,22,18,24)(26,31)(27,34)(33,37)(35,40)(10,17)(12,20)(16,19)(21,23)(25,27,30,34)(26,32,31,28)(29,35,38,40)(33,39,37,36)(9,12,15,20)(10,18,17,14)(11,21,13,23)(16,24,19,22)(25,28,30,32)(26,27,31,34)(29,36,38,39)(33,35,37,40)(9,13,15,11)(10,19,17,16)(12,23,20,21)(14,24,18,22)(25,27)(26,32)(28,31)(29,35)(30,34)(33,39)(36,37)(38,40)(1,3,4,7)(2,6,5,8)(9,14,15,18)(10,20,17,12)(11,22,13,24)(16,23,19,21)(25,29,30,38)(26,33,31,37)(27,35,34,40)(28,36,32,39)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.