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