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