i have recently had this problem, a short answer is to use google’s web app in maps and make your customizations there and then by using the plain text editor and use a to create a button which will link to your map
<button onclick='window.open("[example]")'>GOOGLE MAP</button>
the longer and way more technical way is using a iframe but i personally would not recommend this as this will double the load time (as you are loading 2 web pages) and does not work with some browsers and looks really bad.
if you send me the maps link then i would be happy to code the button for you and if send be colors and stuff i will make somthing to code buttons for you.
^_^ hope this helps