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