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