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