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