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