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