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