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