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