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