Hello,
The Template was designed with an old version of S5 Tab show before the responsive one came out. The class names on Tab Show are much different now as well as the CSS standards used for styling.
You won't be able to get the "exact" same layout but you can get something close by modifying the CSS values in the new Tab Show.
s5_tab_show.css - line 78
.s5_tab_show_slide_button_inactive {
s5_tab_show.css - line 58
.s5_tab_show_slide_button_active {
You can alter the background calls already here for both active and inactive tabs as well as add a border-radius: 10px 0 0; to both values to get a similar look.
Regards,