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