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