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