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