Add the following bits to your pom.xml: 

  <properties>
    <swt.version>3.7.2</swt.version>
  </properties>

  <dependencies>
        <dependency>
            <groupId>${swt.groupId}</groupId>
            <artifactId>${swt.artifactId}</artifactId>
            <version>${swt.version}</version>
        </dependency>
  </dependencies>

    <profiles>
        <profile>
            <id>mac</id>
            <activation>
                <os>
                    <name>mac os x</name>
                </os>
            </activation>
            <properties>
                <swt.groupId>org.eclipse.swt.cocoa</swt.groupId>
                <swt.artifactId>macosx</swt.artifactId>
            </properties>
        </profile>
        <profile>
            <id>windows</id>
            <activation>
                <os>
                    <family>windows</family>
                </os>
            </activation>
            <properties>
                <swt.groupId>org.eclipse.swt.win32.win32</swt.groupId>
                <swt.artifactId>x86</swt.artifactId>
            </properties>
        </profile>
        <profile>
            <id>linux</id>
            <activation>
                <os>
                    <family>linux</family>
                </os>
            </activation>
            <properties>
                <swt.groupId>org.eclipse.swt.gtk.linux</swt.groupId>
                <swt.artifactId>x86_64</swt.artifactId>
            </properties>
        </profile>
    </profiles>


Using files from the following locations - you can check the hashes yourself to verify I haven't done any trickery! 

http://www.eclipse.org/downloads/download.php?file=/eclipse/downloads/drops/R-3.7.2-201202080800/swt-3.7.2-win32-win32-x86.zip
http://www.eclipse.org/downloads/download.php?file=/eclipse/downloads/drops/R-3.7.2-201202080800/swt-3.7.2-cocoa-macosx.zip

http://www.eclipse.org/downloads/download.php?file=/eclipse/downloads/drops/R-3.7.2-201202080800/swt-3.7.2-win32-win32-x86_64.zip