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