While there is no offering in the Pega Platform to build a data visualization like a word cloud, you can always embed your favorite solution from the internet using a custom (not auto-generated) Section or Control.  In case you aren't familiar, custom Controls and Sections use JSP to allow server-side Java code with client-side HTML and JavaScript.

Lets say you have a Data Page called D_WordCloudData that contains a list of the words you would like to use as well as their prevalence.  Here's something to get you started:

<%
  String uniqueId = "CUSTOMCHART" + Long.toString( tools.getDateTimeUtils().currentTimeUnique() );
%>
<div id="<%= uniqueId %>"></div>
<script>
  var dataPageResults = <%
    ClipboardPage dataPage = tools.findPage( "D_WordCloudData" );
    tools.apppendString( dataPage.getJSON( ".pxResults", true ) );
  %>;
  
  var wordCloudContainer = document.getElementById( "<%= uniqueId %>" );
  
  // Write your own JavaScript below
</script>

This example creates an HTML <div> element to root your data visualization in your UI wherever you placed the Section or Control.  The <script> element is where you'll add any custom JavaScript necessary to leverage the world cloud API of your choosing.  A reference to the <div> element is stored in the wordCloudContainer variable.  The dataPageResults variable holds a list of JavaScript objects that match your Data Page's results.

An important side note: the second parameter of getJSON() should absolutely be set to true in this context in order to avoid the possibility of malicious code being transferred from your data into your users' browsers.