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