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