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