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