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