<div class="contents">text</div>
<div class="cp_snslink02">
<ul class="cp_link_list">
<li class="cp_link facebook"><a href="#"><span>Facebook</span><i class="fa fa-facebook fa-2x fa-fw"></i></a></li>
<li class="cp_link twitter"><a href="#"><span>Twitter</span><i class="fa fa-twitter fa-2x fa-fw"></i></a></li>
<li class="cp_link google"><a href="#"><span>Google+</span><i class="fa fa-google-plus fa-2x fa-fw"></i></a></li>
<li class="cp_link instagram"><a href="#"><span>Instagram</span><i class="fa fa-instagram fa-2x fa-fw"></i></a></li>
</ul>
</div>

* {
	-webkit-box-sizing: border-box;
	        box-sizing: border-box;
}
body {
	/*設置する親要素ページ全体ならbodyなど*/
	position: relative;
	height: 100vh;
	margin: 0;
	padding: 0;
}
.contents {
	/*サンプルはfixedの確認のためにheight指定しています。*/
	height: 2000px;
}
.cp_snslink02 {
	position: fixed;
	top: 50%;
	left: 0;
	display: block;
	overflow: hidden;
	margin: 0;
	-webkit-transform: translateY(-50%);
	        transform: translateY(-50%);
}
.cp_snslink02 .cp_link_list {
	margin-left: -95px;
	list-style-type: none;
}
.cp_snslink02 .cp_link {
	position: relative;
	left: -100px;
	padding: 10px;
	cursor: pointer;
	-webkit-transition: left 0.6s ease-in-out;
	transition: left 0.6s ease-in-out;
	text-align: right;
	color: #ffffff;
}
.cp_snslink02 .cp_link a {
	color: #ffffff;
}
.cp_snslink02 .facebook {
	background: #3b5997;
}
.cp_snslink02 .twitter {
	background: #55acee;
}
.cp_snslink02 .google {
	background: #dd4b39;
}
.cp_snslink02 .instagram {
	background: linear-gradient(45deg, #fdf498,#fd5948,#d6249d,#285aea );
}
.cp_snslink02 .cp_link:hover {
	left: 0;
}
.cp_snslink02 .cp_link span {
	display: inline-block;
	margin-left: 55px;
	padding: 0 10px;
}