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