When you create a Snapshot in NX by default you get 'After Update' bodies in a sort of blue color (Deep Ice).
In the on-line help for this Snapshot tool you won't find any details on how to customize this color (btw, that is not inherited by the default color for solid bodies set within Preferences > Object > General tab > Type 'Solid Body' > Color as you might guess).
Solution
There is no option for color or translucency level that is specific to Modeling Snapshots only, but in any case you can customize at least the color of 'After Update' bodies in the NX session (the same option is available in the Customer Defaults as well).
There is an option for Attention objects color in the Visualization Preferences, this is actually the color that will be inherited by bodies created in a Snapshot session.
Hardware/Software Configuration
Platform: all
OS: n/a
OS Version: n/a
Product: NX
Application: DESIGN
Version: V1888
Function: FEATURE_MODEL
Ref: 002-8016150