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