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