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