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