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