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