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