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