Go to Central Administrator -> System Settings -> Manage Services on Server
|Manage Services on Server|
We have to start Visio Graphics Service.
|Visio Graphics Service|
Go to the site url and create New Site from “Site Actions”
Now from Application Management -> Service Application -> Manage Service Application start Visio Service
Create application pool
Make Web drawing by saving image as .VDW
Upload .VDW file in Shared Document in subsite
Now create your site page and add Visio web Access web part
Assign web drawing url from shared document.
Finally you can see web diagram in web part in your site page.