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)(13,16)(14,15)(19,21)(20,24)(22,23) involution — undirected(1,2,5,6)(3,7,4,8)(9,11)(10,12)(13,19)(14,18)(15,17)(16,20)(21,23)(22,24)(25,26,31,30)(27,35,38,32)(28,33,37,39)(29,34,36,40)(1,3,5,4)(2,7,6,8)(10,15)(11,18)(16,23)(19,24)(25,27)(26,32)(28,36)(29,37)(30,35)(31,38)(33,34)(39,40)(9,10)(11,12)(13,16)(14,15)(17,18)(19,20)(21,24)(22,23)(25,28,31,37)(26,33,30,39)(27,36,38,29)(32,34,35,40)(1,3,5,4)(2,7,6,8)(9,12)(10,11)(13,21)(14,17)(15,18)(16,24)(19,23)(20,22)(25,29,31,36)(26,34,30,40)(27,37,38,28)(32,33,35,39)(1,4,5,3)(2,8,6,7)(9,13,14,22)(10,16,15,23)(11,19,18,24)(12,20,17,21)(25,30,31,26)(27,35,38,32)(28,39,37,33)(29,34,36,40)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.