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