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