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