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