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