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