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