In representing a cell we often use || and assume it to represent salt bridge . I found it similar to capacitor symbol , is there is any connection in between them?

There is no connection between the capacitor and salt bridge althogh their symbols are same.
The salt bridge is used for the completion of the loop of the current flow as well as in acheiving the charge neutrality in the corresponding parts of the electrode.
The capacitor is used to store the charge(charging of capacitor) or to use it as energy source(discharging of capacitor) and not has functions similar to salt bridge.