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