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