One vertex per element, one color per generator, with an edge from x to x·s.
(9,10,15,16)(11,13,19,22)(12,17,21,23)(14,18,20,24)(25,26,31,32)(27,33,28,30)(29,37,39,34)(35,38,36,40)(1,2)(3,4)(5,6)(7,8)(9,11,15,19)(10,13,16,22)(12,20,21,14)(17,24,23,18)(26,32)(27,28)(34,37)(35,36)(2,6)(4,7)(10,16)(11,19)(14,20)(17,23)(25,27,31,28)(26,30,32,33)(29,35,39,36)(34,38,37,40)(9,12)(10,17)(11,14)(13,18)(15,21)(16,23)(19,20)(22,24)(25,28,31,27)(26,33,32,30)(29,36,39,35)(34,40,37,38)(1,3)(2,7)(4,6)(5,8)(9,13)(10,11)(12,18)(14,17)(15,22)(16,19)(20,23)(21,24)(25,29,31,39)(26,34,32,37)(27,35,28,36)(30,38,33,40)(1,4,5,7)(2,3,6,8)(9,14)(10,18)(11,12)(13,17)(15,20)(16,24)(19,21)(22,23)(25,30,31,33)(26,27,32,28)(29,38,39,40)(34,35,37,36)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.