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