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