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