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)(19,23,24,22)(25,26,30,32)(27,31,35,40)(28,33,37,38)(29,36,39,34)(1,2)(3,7)(4,5)(6,8)(10,15)(11,18)(12,21)(22,23)(25,27)(26,31)(28,36)(29,38)(30,35)(32,40)(33,39)(34,37) involution — undirected(2,5)(6,7)(10,15)(13,16)(17,20)(22,23)(26,32)(27,35)(33,38)(34,36) involution — undirected(9,11,14,18)(10,16,15,13)(12,19,21,24)(17,23,20,22)(25,28)(26,33)(27,34)(29,31)(30,37)(32,38)(35,36)(39,40)(1,3,4,8)(2,6,5,7)(9,12)(10,17)(11,19)(13,22)(14,21)(15,20)(16,23)(18,24)(25,29)(26,34)(27,33)(28,31)(30,39)(32,36)(35,38)(37,40)(1,2)(3,6)(4,5)(7,8)(9,13,14,16)(10,18,15,11)(12,22,21,23)(17,24,20,19)(25,27)(26,31)(28,34)(29,33)(30,35)(32,40)(36,37)(38,39)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.