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