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