Click Rules > Customize Rules.
Scroll to:
// Removes HTTP-caching related headers and specifies "no-cache" on
requests and responses
public static RulesOption("&Disable Caching", "Per&formance")
var m_DisableCaching: boolean = false;
And change the "false" to "true."
Note, of course, that this only impacts requests that cross the
network, not anything that might already be in the browser cache. To
deal with those, you can either clear the browser cache, or configure
the browser to disable caching (IE's F12 Developer Tools have an
option for that).