Okay...first of all, this is a nice sentence
Secondly, the target isn't the picture (絵) , its the man's ideal (理想) that is drawn in the picture (literally). The picture is just "a way" or "a place" (that is why に is used).
Sorry if this have sounded complicate, but you might say it in a different way 「絵で理想を描いたような男性だった。」
you can say it 「理想を描いたような男性」. 「絵に」 just defines where he draw this.
僕は友達にプレゼントをあげる
僕はプレゼントを友達にあげる
same meaning, just word order is different
Just want to clarify that there isn't any actual "picture" in this sentence; it's a metaphor for how perfectly the man matches the unnamed other person's ideals. It's like saying "The man was so perfect it was as if someone had taken [her/his/my] ideal guy and painted a picture of them."
grammer question
if 「絵」is the target of 「描く」,then why there is a 「を」after 「理想」?