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