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