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