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