As this is a homework question here are some pointers.
In order to 'sketch' a graph of current against time you need to do a few (simple) calculations first.
(1) Steady state (t > 0) - means the current through the inductor is at its maximum value. What component(s) control this final current value and how could you calculate this value. This will give you the initial current value (Io).
(2) After the switch is open (t >= 0) this initial current value (Io) will start to decay exponentially.
(a) What is the time constant of this decay circuit? (remember the switch is open so that part of the circuit is disconnected)
(b) What will the current be after 1 second if Io is the initial current.
With the values from (1a) and (2b) and knowing it's a decaying exponential you should be able to sketch the graph of current against time.