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