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