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