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