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