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