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