Hi,
I think the appearance of the FOD template has to do with differences in b-values, the number of directions and shells in the data you have. At lower b-value and in single shell, the contrast will get the kind of results you are showing (although you can play with the intensity scale by maintaining right click in mrview).
See this previous related thread:
https://community.mrtrix.org/t/fba-single-shell-high-gm-fod-values/
The term “tractogram” is more often used to refer to the 3D tracts from the track files (.tck) William has shown coloured in his 2nd/3rd pictures, I too misunderstood your question at first.
I hope that helps
Charly