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