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