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)(11,13)(12,20)(14,15)(16,18)(17,22)(19,21)(23,24)(25,26,30,33)(27,28,35,31)(29,32,37,39)(34,36,40,38)(1,3,5,8)(2,6,4,7)(9,10,14,15)(11,16,18,13)(12,17,22,20)(19,21,24,23)(1,2,5,4)(3,6,8,7)(10,15)(11,18)(17,20)(19,24)(25,27,30,35)(26,31,33,28)(29,34,37,40)(32,38,39,36)(1,2,5,4)(3,6,8,7)(9,11)(10,16)(12,19)(13,15)(14,18)(17,21)(20,23)(22,24)(25,27)(26,28)(29,34)(30,35)(31,33)(32,36)(37,40)(38,39)(9,12)(10,17)(11,19)(13,23)(14,22)(15,20)(16,21)(18,24)(25,28)(26,27)(29,36)(30,31)(32,34)(33,35)(37,38)(39,40) involution — undirected(1,4,5,2)(3,7,8,6)(9,13,14,16)(10,11,15,18)(12,21,22,23)(17,24,20,19)(25,29,30,37)(26,32,33,39)(27,34,35,40)(28,36,31,38)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.