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