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