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)(12,20,22,21)(13,19,14,17)(16,24,18,23)(25,26,31,34)(27,29,33,30)(28,36,40,35)(32,38,37,39)(1,3,4,8)(2,5,6,7)(9,11,15,10)(12,21,22,20)(13,19,14,17)(16,24,18,23)(25,27)(26,29)(28,37)(30,34)(31,33)(32,40)(35,38)(36,39)(9,12)(10,16)(11,18)(13,24)(14,23)(15,22)(17,21)(19,20)(25,28,31,40)(26,32,34,37)(27,35,33,36)(29,38,30,39)(2,6)(5,7)(12,22)(16,18)(20,21)(23,24)(25,29,31,30)(26,33,34,27)(28,38,40,39)(32,36,37,35)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.