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