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