Well, bluntly speaking the answer is No. you cannot connect to an Elastic cache Redis node outside of Amazon EC2 instances. This because an Amazon ElastiCache Cluster, inside or outside a VPC, is never allowed to be accessed from the Internet.
You may use out of hat tricks like tunneling. But that takes the fun out of it. Because you wont have any benfit of using a super fast cache.
I hope this helps :)