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