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