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