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