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