Yes, it can be cached.
To Note:
In the Dashboard > Settings > GenerateBlocks there are two CSS Print Method options to choose from:
1. External File
2. Inline
If changing those options you must click Regenerate CSS after.
We provide both options as some server configurations do not like External Files.
When it comes to caching the External File can be cached like any other file and as part of Combined CSS.
When using Inline most cache plugins provide options to Combine Inline CSS.