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