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