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