There are several ways you can achieve that look (translucent, SSS, volume scatter etc). I knocked up this node setup pretty quickly - it seems to look reasonable. You can alter the transparency of the material by tweaking the Fac value of the centre mix shader (currently set to 0.5).
It wont be the fastest or cleanest node setup (the glass and translucent shaders can be pretty slow and noisy) - but it may give you a reasonable starting point from which to experiment further. Incidentally - the noise in the above image is simply due to the low number of samples I rendered with - I am using my laptop which is pretty slow and I couldn’t be bothered to wait any longer 
You may also want to look at your lighting setup - the one you have looks unlikely to show off the material to its best. Add a ground plane and perhaps a HDRI environment map as your lighting (plenty available for free - just google).