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