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)(11,17)(12,16)(13,18)(14,19)(15,20)(21,24)(22,23)(25,26,30,32)(27,28,33,31)(29,34,38,40)(35,36,37,39)(1,2)(3,6)(4,7)(5,8)(9,11)(10,15)(12,21)(13,16)(14,20)(17,19)(18,23)(22,24)(25,27,30,33)(26,31,32,28)(29,37,38,35)(34,36,40,39)(11,20)(12,23)(15,17)(16,22)(26,32)(27,33)(34,40)(35,37) involution — undirected(1,3,5,4)(2,6,8,7)(9,12,14,23)(10,16,19,22)(11,21,20,18)(13,17,24,15)(25,28,30,31)(26,33,32,27)(29,36,38,39)(34,37,40,35)(9,11)(10,17)(12,21)(13,22)(14,20)(15,19)(16,24)(18,23)(25,26)(27,31)(28,33)(29,34)(30,32)(35,39)(36,37)(38,40) involution — undirected(1,4,5,3)(2,7,8,6)(9,13,14,24)(10,18,19,21)(11,22,20,16)(12,17,23,15)(25,29,30,38)(26,34,32,40)(27,35,33,37)(28,36,31,39)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.