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