If coloring by a nodal variable, the default coloring will be continuously varying - even within a given element. If you are coloring by a per-element variable, the coloring will not vary within a given element. If you desire to see per-element variables in a continuously varying manner, you can toggle on Use continuous palette for per element vars under Edit → Preferences... → Color Palettes.

Also consider using the Quick Color Settings Widget (see Use Quick Color Settings) to color parts.