The structures shown here are the result of chair-chair interconversion. You should try to find the plane of symmetry in each of these conformations. Because of this symmetry both are achiral. Also observe the extreme crowding of the chlorine atoms (green) in the diaxial conformer on the right. The spacefilling rendering is best for this purpose. Crowding of this kind reduces the stability of the structure, so the diequatorial conformer predominates in the equilibrium mixture.
These models can be moved about by clicking on the structure and dragging the mouse. Holding the shift key during this operation allows zooming.