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