You can make graphene aerogel superhydrophobic with the use of superhydrophobic polymers or stearic acid.  

Graphene per se is hydrophobic..

@ karthikeyan- Thank you,Could you please highlight on the polymers used for superhydrophobicity? 

@sridhar- Thank you, I would like to make it superhydrophobic.

Unfunctionalized graphene is hydrophibic. See the following link for Molecular Dynamics simulation of graphene sheets association in water:

http://www.sciencedirect.com/science/article/pii/S0039602811000628

https://www.researchgate.net/publication/253525962_Self-assembly_of_graphenes

Article Self-assembly of graphenes

Swapneel Vijay Thakkar , our new article in the journal ACS Appl. Mater. Interfaces: "Novel Superhydrophobic Aerogel on the Base of Polytetrafluoroethylene"

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Article Novel Superhydrophobic Aerogel on the Base of Polytetrafluoroethylene

Polytetrafluoroethylene-based aerogel was synthesized for the first time. Graphene oxide was used as a binder. After reduction with hydrazine and annealing at 370°C, the aerogel with a density of 29 ± 2 mg/cm3 became superhydrophobic. The aerogel was characterized by IR spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The sorption capacity of the aerogel for seven solvents and its sorption recyclability for hexane were measured.