AS 1101.1:1993 – Graphic symbols for general engineering Part 1 Hydraulic and pneumatic systems
The online version can be found here Paper copy, but it appears to have been superseded by a 2007 version found here
Other possible books that you may find of use can be found on the catalogue under these keywords linked below.
Other possible books
“Pneumatics and Hydraulics”
“Hydraulics”
“Pump”