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