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