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