You can apply for Hong Kong Employment Visa through the Chinese Embassy in India, but the contract paper is not sufficent for the application, you and your boss also need to prepare the below documents, in fact, your boss and apply for Hk Employment Visa through Hong Kong Immigration Department, then send the Hk visa to you.

Your boss also need to provide many other documents for Hk Employment Visa application, such as:
Business Registration Certificate, Certificate of Incorporation and/or Memorandum of Incorporation and Articles of Association;

Financial standing of your boss's company (income tax return, trading profit and loss account, profit tax return);

Company staff list with salary offered and position held and list of expatriate staff previously or currently recruited from overseas;