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