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