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