According to the article on hindu art at the metropolitan museum's website, indian artists expressed the omnipresence and omnipotence of a deity by - creating colossal sized figures - creating figures with a multiplicity of arms - creating a multiplicity of faces - showing the deity surrounded by wild animals

Creating figures with a multiplicity of arms.
    The easiest way to answer this question is to simply go and read the article on Hindu art at the Metropolitan Museum's website. The ToS on prohibits me from actually including the URL, but a quick google search will suffice to find the article. And once you find it, the following quote will provide the answer "... Deities are frequently portrayed with multiple arms, The Indian artist found this a simple and an effective means of expressing the omnipresence and omnipotence of a deity."

Walls is easier to memorize