Are you talking about showing an approximately icosahedral virus, like a phage with a tail?

  In any case the picture you show was made with the Chimera flatten icosahedron tool and it rearranges whole protein model surfaces in this unfolded icosahedron.

Each of the proteins is just repositioned without distortion.  It can't be done in the same way with a cryoEM map -- that would require some projection to make the triangular facets which will involve some distortion and also will need to be done in a special way so they match at the neighboring triangle edges. One way to do that would be to chop the cryoEM map surface into 20 triangular cone pieces from the origin out through the 20 faces of an icosahedron.  Then just lay out those 20 pieces as shown in the figure by rotating and repositioning them.

Tom