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