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