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