In the Mesh Appearance dialog you can adjust the display of mesh lines.
Detail: Mesh Line Settings
Moving the Detail slider from 0 to 10 allows the displaying of mesh lines when you are viewing the model at further zoomed out levels regardless of mesh coarseness.
These settings are not applicable to 2nd order elements and clipped elements of section cuts, or when you are in Automesh panel mode.
Used in conjunction with mesh line option in the Options panel, Colors subpanel.
Transparency: Finite Element Settings
Moving the Transparency slider from 2.0 to 9.5 adjusts the transparency levels of finite element models from more opaque to more transparent.
Check this box on to display mesh lines when finite elements are transparent.