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