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