I was able to track and resolve the issue. The issue was the wrong driver class being saved in model connection profile. Though I updated the driver class in the connection profile in Database Developement perspective , but in model it was not reflecting. So I had to delete the connection profile, delete the model then created new connection profile with correct driver class and then created the model importing the newly created connection profile. Now I am able to preview the data.
Note: You can check the connection profile for your model :
Model explorer > go to the model > right click > Modeling > View Connection Profile Info