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