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