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