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