Module admin configuration permission
Since you're not declaring an access callback, the access callback defaults to the user_access() and passes your access argument into it based on the hook_menu().

Now, when we check the code of user_access(), we notice the following code.

// User #1 has all privileges:
if ($account-&gt;uid == 1) {
  return TRUE;
}


So the first created admin account will always have access. You then said: 


  But I could not able to prevent other Role's users that has access to
  admin pages from accessing its configurations,


If you added another user with the Administrator role, and the permission is unchecked for the Administrator role in the Permissions page, your code should work and I can confirm it. So please check if: 


You have the permission unchecked
You have cleared all caches or maybe just the menu cache
The admin user you are currently using to test the page's access is NOT the first admin user created