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