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