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