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