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