You can add the following script to the Post-HTML setting on the block that is displaying the matrix item attribute (i.e. Workflow Entry block)
<script>
Sys.Application.add_load(function () {
var $tr= $("[id$='gMatrixItems_actionFooterRow']");
$tr.find("td.grid-actions").css({"text-align": "left", "padding-left": "0px"});
$tr.find("a.btn-add").css("margin-left", "0px");
});
</script>