Unfortunately, I couldn't find a direct download link for Festo FluidSim Pneumatics 3.6 with 42 library. However, I can suggest some possible sources:

The inclusion of the 4.2 library significantly expands the available hardware. This update adds modern sensors, advanced proportional valves, and complex logic controllers that were not present in earlier iterations. This library is essential for anyone looking to simulate contemporary industrial automation setups. Real-Time Simulation and Animation