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