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