One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,4)(3,7,8,6)(12,20)(15,21)(19,24)(22,23)(25,26)(27,34)(28,36)(29,33)(30,31)(32,35)(37,40)(38,39)(1,3)(2,6)(4,7)(5,8)(9,10,13,16)(11,17,18,14)(12,21,20,15)(19,22,24,23)(25,27,29,30)(26,31,33,34)(28,35,37,38)(32,36,39,40)(1,2,5,4)(3,6,8,7)(9,11)(10,14)(12,19)(13,18)(15,22)(16,17)(20,24)(21,23)(25,28)(26,32)(27,35)(29,37)(30,38)(31,36)(33,39)(34,40)(1,4,5,2)(3,6,8,7)(11,18)(14,17)(19,24)(22,23)(25,26)(27,31)(28,32)(29,33)(30,34)(35,36)(37,39)(38,40)(9,12,13,20)(10,15,16,21)(11,19,18,24)(14,22,17,23)(26,33)(31,34)(32,39)(36,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.