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