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