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