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