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