how to see the configuration changes in jenkins for a particular job

Most of the CI tools have this option to see the changes. Jenkins too has this support.

You can install the plugin Job Configuration History Plugin , so that for every change, you can have a track.

Add "Job Configuration History Plugin" for tracking the changes done in configuration. Once added it will appear on left side, please refer below image.

Link to Plugin : https://wiki.jenkins-ci.org/display/JENKINS/JobConfigHistory+Plugin

Also you can revert back to old configuration using this same Plugin.