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