In the document where you inserted the hyperlink, display the Styles pane,
for example by pressing Ctrl+Alt+Shift+S. Click the Manage Styles button. On
the Edit tab of the dialog box, locate FollowedHyperlink. Click the Modify
button. Specify the font, font size and other settings that you want (to see
more options, click Format, Font; when you are done, click OK to close the
Font dialog box). If you want to transfer the settings to the attached
template, be sure to select "New documents based on this template" before
clicking OK.