List tags and URLs inside

I want to list first all children tags of a parent page, and after that list all children pages of those tags. I have achieved to list children pages of a given tag:

{% for p in taxonomy.findTaxonomy({'tag':'Agonista adrenérgico'}) %}
[{{ p.title }}]({{p.url}})
{% endfor %}

But I want to automatically show me a list of tags and after each tag the children with that tag. I have tried this, but it doesn’t work:

{% for p in page.children.order('date', 'asc') if p != page %}
<span style="background-color: #ffcc99; font-size: 8pt;">{{ taxonomy.getTaxonomyItemKeys('taxonomy.tag') }}</span> [{{ p.title }}]({{p.url}})
{% endfor %}

Thanks in advance!