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