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