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