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