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