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