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