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