URL masking

I have successfully added my own domain and mapped it to my Zoho site via the A Record 74.201.154.208 and the CNAME zhs.zohosites.com. Entering my doamin url successfully forwards me to my Zoho site, but the url becomes MYDOMAIN.zohosites.com. I want the url bar to stay within MYDOMAIN.com. How can I do this?