A fully three-dimensional kinematic model is applied to simulate the evolution of the magnetic field in a small (120 pc in size) volume of the turbulent interstellar medium in the presence of the field diffusion. Turbulent motions are approximated by a sequence of non-overlapping in time vortices having the form of rotating gas columns much longer than the parcel size. A combined action of vertical vortices and those inclined at the angle of 30° to the galactic plane is considered. Due to the Coriolis force and density stratification their motions have a non-zero helicity. The magnetic field is found to evolve towards the structure resembling a fragment of a twisted flux tube, well-ordered over the volume analyzed. Its sense of twisting is determined by the vortex helicity.