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