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