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)(11,18)(12,20)(13,15)(14,16)(17,22)(19,23)(21,24)(25,26,30,31)(27,29,33,38)(28,35,37,32)(34,40,39,36)(2,3)(6,7)(9,11,14,13)(10,15,16,18)(12,19,22,21)(17,23,20,24)(25,26,30,31)(27,29,33,38)(28,32,37,35)(34,36,39,40)(4,8)(6,7)(10,16)(15,18)(17,20)(23,24)(26,31)(29,38)(32,35)(36,40) involution — undirected(1,3,5,2)(4,7,8,6)(9,12)(10,17)(11,19)(13,21)(14,22)(15,23)(16,20)(18,24)(25,27,30,33)(26,29,31,38)(28,34,37,39)(32,36,35,40)(9,13,14,11)(10,18,16,15)(12,21,22,19)(17,24,20,23)(25,28,30,37)(26,32,31,35)(27,34,33,39)(29,36,38,40)(1,4,5,8)(2,6,3,7)(9,10)(11,15)(12,17)(13,18)(14,16)(19,23)(20,22)(21,24)(25,29)(26,33)(27,31)(28,36)(30,38)(32,39)(34,35)(37,40)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.