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