Colored Cross-references

There isn't a field switch for that, besides which cross-references and hyperlinks are different things (even though cross-references can hyperlink). The essential differences are that cross-references:

1. do not have a blue, underlined, font that changes colour when followed, which makes them better suited to printed content;

2. update automatically to reflect changes in the referenced content, whereas hyperlinks must be edited manually; and

3. can only point to content within the same document, whereas hyperlinks can reference external content.

If your clients want to see where the cross-references are, that's a simple matter of setting Word's 'field shading' option to 'always'.

If you really want to have the cross-references look like hyperlinks:
1. Press Alt-F9 to expose the document's field codes. Each cross-reference will look something like { REF BkMk \h }, where 'BkMk' is a bookmark name.

2. Edit each cross-reference field code so it looks like { REF BkMk \* Charformat \h }

3. Format the 'R' in 'REF' blue, with underlining;

4. Press Alt-F9 to hide the field codes, then Ctrl-A, F9 to update the display.

Note: Even with these mods, the cross-references won't change colour when followed - but all your printouts of the document will now have the blue underlining, which you'll only be able to get rid of by reformatting the 'R's to their original state.