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