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