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