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