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