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