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