Allah guides every one who wants to be guided, and when Allah guides some one, no one will be able to misguide him.
Those who reject and insist on rejecting the truth, will leave them to themselves with out guidance from Allah, because they insisted on rejecting. This is the meaning of misguiding. Allah does not misguide any one, but leaves the tyrant sinners with out guiding as they have insisted on rejecting His guidance, and that situation of leaving them to themselves is called misguiding. It means leaving them to what they wanted , with out guidance of Allah.
Such tyrant sinners will never be guided unless they change their minds and selves.