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