You might want to approach this question by considering the way that storms operate in both a literal and a symbolic way in this excellent play. For example, it is clear that the opening storm that gives the play its name is quite clearly real, as it brings Prospero's old enemies to his island so that he can get his revenge upon them and have a chance to restore some of those relationships. However, in many other places in Shakespeare, literal storms are also used symbolically to represents metaphorical storms and tempests. For example, in King Lear, the storm on the heath where he wanders is used to represent the chaos that has befallen the kingdom of Britain. Likewise in the Tempest, the storm is used to point towards the theme of broken relationships and chaos. The "harmony after the storm" that your question refers to could point towards the way that through the play, broken relationships are healed and made whole again. Your pictures therefore might want to include how this theme is played out and how characters are restored in their relationships to one another and also to their own true identity. For example, the character of Ariel is obviously very important in this context, as is the character of Prospero. Thinking about how these characters change and transform from the beginning of the play to the end might give you a very interesting basis for your drawings.