  We report on pulse profile decomposition analysis of a bright transient X-ray
pulsar 1A 0535+262 using the broadband Insight-HXMT observations during a giant
outburst of the source in 2020. We show that the observed pulse profile shape
can be described in terms of a combination of two symmetric single-pole
contributions for wide range of energies and luminosities for a fixed geometry
defining basic geometry of the pulsar. This corresponds to a slightly distorted
dipole magnetic field, i.e., one pole has to be offset by $\sim 12^{\circ}$
from the antipodal position of the other pole. We reconstruct the intrinsic
beam patterns of the pulsar assuming the geometry recovered from the
decomposition analysis, and find evidence for a transition between "pencil" and
"fan" beams in energy ranges above the cyclotron line energy which can be
interpreted as transition from sub- to super-critical accretion regimes
associated with onset of an accretion column. At lower energies the beam
pattern appears, however, to be more complex, and contains substantial "fan"
beam and an additional "pencil" beam component at all luminosities. The latter
is not related to the accretion rate and is stronger in the fading phase of the
outburst. We finally discuss results in context of other observational and
theoretical findings earlier reported for the source in the literature.
