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