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