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