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