Hydrosym

Hydrosym is the most effective software package to create hydraulic diagrams. Hydrosym runs 100% stand alone and works with a comprehensive library of almost all available hydraulic components.

Furthermore, components/symbols or other objects (cylinders, pumps, motors etc.) can easily be made and added to this library.
Drag your components from the library into the diagram and intelligent connections can automatically be made. Detailed information (datasheets) about components is conveniently accessible. When moving components around in your diagram, all connections involved will be maintained.