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