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