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