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