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